Atoms and Molecules

Question 1

what is the definition of an element?

Answer 1

a substance that cannot be broken down into other substances by chemical reaction

Question 2

what is the definition of a compound?

Answer 2

a substance consisting of 2 or more different elements combined in a fixed ratio

Question 3

what atoms make up 96% of all living matter?

Answer 3

C, O, H and N

Question 4

what is the definition of an atom?

Answer 4

the smallest unit of an element that retains the chemical properties of the element

Question 5

when do electrons have the greatest potential energy?

Answer 5

the further away from the nucleus they are

Question 6

what dictates the chemical behavior of an atom?

Answer 6

the no. valence electrons

Question 7

what are the names and order of shell orbitals ?

Answer 7

1s, 2s, 2p(3), 3s, 3p(3), 3d(5)

Question 8

what are the strongest chemical bonds?

Answer 8

covalent and non-aqueous ionic bonds

Question 9

what is the definition of a covalent bond?

Answer 9

the sharing of a pair of valence electrons by 2 atoms

Question 10

what makes a polar covalent bond?

Answer 10

the differences in the electronegativities between two atoms in a covalent bond

Question 11

what makes an ionic bond?

Answer 11

where one atom strips valence electrons from its partner, due to its strong electronegative force, that create two ions that can then join together.

Question 12

what is the name of a positive ion?

Answer 12

cation

Question 13

what is the name of a negative ion?

Answer 13

anion

Question 14

what makes a crystal?

Answer 14

an aggregate of cations and anions bound by electrical attraction and arranged in a 3D lattice

Question 15

does an ionic compound consist of molecules?

Answer 15

no

Question 16

what does a covalent compound consist of?

Answer 16

molecules having a definite size and number of atoms

Question 17

what is an example of an ionic molecule?

Answer 17

NH4Cl

Question 18

why is hydrogen bonding important?

Answer 18

unique properties of water
structure of proteins
structure and function of DNA 
structure and function of polysaccharides
binding of substrates and enzymes 
binding of hormones to receptors 
matching mRNA and tRNA

Question 19

what are Van der Waals forces?

Answer 19

weak interactions caused by an uneven distribution of electrons in the shells.

Question 20

what is an example of Van der Waals forces?

Answer 20

geckos feet with van der waals forces with the molecules of smooth surfaces allowing them to stick

Question 21

why are molecular shapes important?

Answer 21

recognising and bonding with each other e.g. receptors

Question 22

t/f all chemical reactions are theoretically reversible?

Answer 22

true

Question 23

how do drugs work?

Answer 23

non-human compounds share molecular shapes with natural compounds